Lubricating composition containing schiff base-inorganic halide adduct



prepared from an 'amine and an aldehyde.

United States Patent 3,320,166 LUBRICATING COMPOSITION CONTAIN- INGSCHIFF BASE-INORGANIC HALIDE ADDUCT Frederic C. McCoy, Beacon, and EdwinC. Knowles, Poughkeepsie, N.Y., assignors to Texaco Inc., New York,N.Y., a corporation of Delaware N0 Drawing. Filed Feb. 14, 1966, Ser.No. 527,057 11 Claims. (Cl. 25249.7)

The present invention relates to a novel Schiif baseinorganic halideadduct and to a lubricating composition containing the Schilfbase-inorganic halide adduct to improve the load carrying properties ofthe lubricating composition.

This application is a continuation-in-part application of applicationSer. No. 307,791, filed on Sept. 10, 1963, now Patent No. 3,272,852.

New designs and improvements in machinery are continually raising theoperating performance standards of lubricating compositions. In manyinstances, the pressures and temperatures under which the bearingsurfaces of machinery operate are higher than those which natural orsynthetic lubricating oils can withstand. Instances where difficultlubricating conditions are encountered occur in the lubrication ofheavily loaded pinion and spur gears, gear trains, bearings, extrusionapplications and the like. As a result, there is an ever increasing needfor lubricating compositions having improved properties for theseservices.

A novel class of oil-soluble Schiff base-inorganic halide adducts hasbeen discovered which imparts greatly improved properties to lubricatingoils. The lubricant compositions containing the adducts are particularlynotable for their improvement in load carrying and anti-sculf propertiesalthough they also exhibit additional valuable features, such ascorrosion resistance, oxidation resistance and stability. The Schiffbase-inorganic halide adducts'are also useful as insecticides,fungicides, bactericides and in the preparation of pharmaceuticals.

The novel oil-soluble adduct of the invention is formed from thereaction of a Schiff base and an inorganic halide. This adduct isrepresented by the following formula:

--wherein R is a hydrocarbyl radical having from 1 to 30 carbon atoms, Ris hydrogen or a hydrocarbyl radical having from 1 to 18 carbon atoms,the sum of the carbon atoms in R and R being at least 12, y is aninteger from 1 to 6, M is a polyvalent cation selected from the classconsisting of boron, aluminum titanium, tin, zinc, copper,

. comprises a major proportion of a lubricating oil base and a minoramount of the adduct described above. Mineral and synthetic lubricatingoil bases can be employed to prepare a lubricating compositioncontaining the adduct.

The Schiif base which corresponds to the formula:

H RN=CR' in which R and R have the values noted above and which isemployed to form the adduct of the invention is Specifically, equivalentamounts of a primary amine and an aldehyde are contacted either in thepresence of or without a solvent. This reaction frequently occursspontaneously al- Patented May 16, 1967 though at times moderate heatingis required. The reaction causes a mole of water to split out in theformation of the Schiff base. The water formed by the reaction isgenerally removed by azeotroping with a solvent, such as toluene. It isessential that the sum of the carbon atoms represented by R and R in theformula for the Schitf base amount to at least 12 in order to insure theoil solubility of the adduct that is ultimately formed.

Amines which can be employed to prepare the Schiff base are the primaryaliphatic amines. These amines are represented by the following formula:

in which R is an aliphatic hydrocarbyl radical having from 1 to 30carbon atoms. The preferred amines are those in which R is a branchedchain alkyl radical having from about 12 to 24 carbon atoms.

Examples of suitable amines include butylamine, amylamine, hexylamine,octylamine, laurylamine, tridecylamine, tetradecylamine, hexadecylamine,octadecylamine and tricosylamine. Particularly preferred amines arecertain commercially available mixtures of tertiary alkyl primaryamines. For example, a mixture of tertiary alkyl primary amines in whichthe alkyl radical comprises a mixture of alkyl groups having 11 to 14carbon atoms is available under the name Primene 81-R. Anothercommercially available amine is the mixture of tertiary alkyl primaryamines in which the alkyl radical comprises a mixture of alkyl groupshaving 18 to 24 carbon atoms which is available under the name ofPrimene JM-T.

Aldehydes which can be employed to react with the primary amines informing the Schifl base are represented by the following formula:

in which R is hydrogen or a hydrocarbyl radical having from 1 to 18carbon atoms. The hydrocarbyl radical can be an aliphatic or an aromatichydrocarbyl radical and preferably has from 1 to 10 carbon atoms.Examples of aldehydes which can be employed include formaldehyde,2-ethylhexaldehyde, acetylaldehyde, propionaldehyde, butyraldehyde,nonylaldehyde, palmitic aldehyde, lauraldehyde, stearaldehyde andbenzaldehyde.

The following examples are typical of the method of preparing the Schilfbase.

Example I 256 g. 2-ethylhexaldehyde (2 moles) were added slowly to 630g. (2 moles) Primene JMT (C tertiary alkyl primary amine) in a stirredflask. Thereaction was moderately exothermic. Toluene ml.) was added andthe mixture heated to reflux. Water (30 ml.) was recovered equivalent to83% of theoretical. The toluene was removed using a stream of nitrogen,and 836 g. clear amber Schiff base were obtained.

Example 11 344 g. of a 35% aqueous solution of formaldehyde (4 moles CHO) were added slowly to 1260 g. Primene JMT (4 moles) in a stirredflask. The reaction was mildly exothermic. Toluene (300 ml.) was addedand the mixture heated to reflux. The theoretical amount of water (296ml.) was recovered. Toluene was stripped with the aid of a stream ofnitrogen to yield 1274 g. of clear, amber Schitf base.

The adducts of the invention are prepared by mixing a Schiff basedefined above with an inorganic halide compound from the class setforth. The reaction is usually exothermic and provision must generallybe made for cooling the reaction mixture. Caution must be exercised tokeep the reaction temperature below the decomposition temperature ofboth components of the reaction product which generally means conductinga reaction at a temperature below about 200 C. The reaction generallygoes to completion in a short reaction time.

Halides of metals and metalloids which can be employed to react with theSchiff base and to form the load carrying adducts of the inventioninclude boron trifluoride, boron trichloride, aluminum trichloride,aluminum trifluoride, titanium tetrachloride, titanium tetrafluoride,stannous chloride, stannous fluoride, stannic chloride, 'cupricchloride, cupric bromide, cadmium chloride, cadmium iodide, magnesiumchloride, mercuric chloride, zirconium chloride, antimony chloride,antimony fluoride, bismuth chloride, manganese chloride, and ferricchloride. The preferred halides are those formed from ti- .tanium, tin,antimony, copper and zinc.

Only specific halides as set forth above are effective for producing theadducts of the invention. Examples of halides which do not form adductsinclude cuprous chlo- .ride, cupric fluoride, magnesium fluoride,manganous fluoride, antimony oxychloride, barium chloride, lithiumchloride and calcium chloride.

An unexpected phenomenon is the discovery that the inorganic salt musthave a substantial and apparently a critical degree of water solubilityin order to form a complex with an amine of the type disclosed herein.The reason for the relationship between water solubility and complexformation is not fully understood. It has been determined, however, thatthe following critical conditions must be met in order to form a complexof the type disclosed:

A. The metallic element of the salt must be capable of :sharing theunpaired electron of the amine nitrogen.

B. The salts must have a water solubility greater than 0.2 mole perliter at a temperature in the range of 15- 100 C.

Examples of inorganic salts and their behavior toward complex formationwith a C primary amine (Primene .JMT) is given in Table I below:

TABLE I H20 Solubility, Mols Complex Formation Salt/l. of H With C21Primary Amine Salt The Schiff base and halide are reacted in theproportion of 1 to 6 moles of Schiff base to 1 mole of the halidecompound with the preferred amount of the Schiff base being .from 1 to 4moles.

The following examples are typical of the method of preparing theadduct.

Example III 2.4 g. (0.02 mole) TiF were dissolved in 50 ml. acetone andthe solution added to 33.5 g. (0.08 mole) of the SchiiT base of ExampleI. The acetone was removed on steam bath. The slightly hazy viscousorange colored liquid was filtered to give a TiF complex of the Schiffase.

Examples of adducts of the invention are given below. For additionalconvenience, the Schitf base part of the adducts is expressed in termsof the components from which the Schitf bases are formed. The mole ratioin brackets is the ratio of the Schiff base to the inorganic halide.

4 Primene IMT/formaldehyde:boron trifluoride (3:1), PrimeneJMT/formaldehyde:boron trichloride (3:1), PrimeneJMT/formaldehyde:aluminum trichloride Primene ]MT/formaldehyde:tintetrachloride (4:1), Primene JMT/2'ethylhexaldehyde antimony trifluoride(2:1),

Primene JMT/2-ethylhexaldehyde titanium tet-rafluoride (4:1),

Primene J M-T/,formaldehyde:stannous fluoride (2:1), Primene81R/formaldehyde:cadmium chloride (2:1), Primene81R/formaldehyde:cadmium iodide (2: 1), Primene81-R/formaldehyde:zirconium chloride (2:1), Primene8lR/formaldehyde:bismuth chloride (2:1), Primene JMT/formaldehyde:cupricchloride (2:1), Primene JMT/formaldehyde:magnesium chloride PrimeneJM-T/2-ethylhexaldehyde mercuric chloride (2:1),

Primene J MT/ 2-ethylhexaldehyde manganous chloride (2:1),

Primene JM-T/2-ethylhexaldehyde :ferric chloride PrimeneJMT/formaldehyde:zinc chloride (2:1), and Primene JMT/2-ethylhexaldehyde stannous chloride (2:1).

The lubricating compositions of the invention are prepared by blendingin a conventional way a minor amount of the oil-soluble, load carryingSchiff base-inorganic halide adduct described hereinabove into asuitable lubricating oil base. Generally, the adduct is employed in anamount in the range of 0.05 to 10 percent by weight based on the weightof the lubricating composition with the preferred proportions of theadduct being from 0.1 to 3 weight percent.

The base lubricating oil can be a mineral lubricating oil or a syntheticlubricating oil. The mineral lubricating oil can be a predominantlyparaflinic or naphthenic oil or it can be a mixture of both types ofmineral oils. Generally, the mineral oil will be a refined oil ofpredominantly paraffinic nature having a viscosity in the range from 30to Saybolt Universal seconds at 210 F.

Various types of synthetic lubricating oil bases can be employed inpreparing the lubricants of the invention. Aliphatic ester, polyalkyleneoxides, silicones, esters of phosphoric and salicyclic acid and thehighly fluorinesubstituted hydrocarbons can be employed. Examples of thealiphatic esters include di-(Z-ethylhexyl) sebacate, the dialkylazelates, dialkyl suberates, and the dialkyl adipates such as di-hexylazelate, di-(2-ethylhexyl) azelate, di-3,5,S-trimethylhexyl glutarate,di-(Z-ethylhexyl) adipate, tri-amyl tricarballylate, etc. Thepolyalkylene oxides include polyisopropylene oxide, polyisopropyleneoxide diether, polyisopropylene oxide diesters, etc. The siliconesinclude methyl silicone, methylphenyl silicone, and the silicatesinclude tetraisooctyl silicate. The highly fluorinated hydrocarbonsinclude fluorinated oil, perfiuorohydrocarbons, etc.

Other effective synthetic lubricating oils include the neopentyl glycolesters such as the neopentyl glycol propionates, neopentyl glycolbutyrates and neopentyl glycol caprylates and the trimethylol alkanessuch as trimethylol ethane, trimethylol propane, trimethylol pentane,trimethylol heptane and trimethylol dodecane and the like. Examples ofthe phosphate esters include tricresyl phosphate, trioctyl phosphate andtridecyl phosphate as well as mixed aryl and alkyl phosphates.

Example V The load carrying and anti-scuff properties of lubricatmgcompositions of the invention was determined in the mean Hertz loadtest. This test is run in a machine havmg four /2 inch diameter bearingballs which are driven under load while being lubricated by thecomposition under test. The description of this test is set forth in US.Patent 2,600,058.

The Schiff base A designation referred to in the following compositionswas prepared by reacting a mole of Primene JMT with a mole of2-ethylhexaldehyde. Schifi base B refers to the Schiii base prepared bythe reaction of a mole of Primene JMT with a mole of formaldehyde.

The lubricating compositions tested were prepared using both mineral andsynthetic base oils. Base oil A was a commercially available syntheticlubricating oil consisting of di-Z-ethylhexyl sebacate plus sebacic acidand having an SUS viscosity at 100 F. of about 70. Base oil B was amineral lubricating oil having an SUS viscosity at 210 F. of about 100.The lubricant compositions of the example contained 1 percent "by weightof the indicated Schilf base-halide adduct. The results of this test aregiven in Table II below.

TABLE II.LOAD CARRYING AND ANTI-SCUFF PROPERTIES Lubricant CompositionMean Hertz Adduct Mole Ratio Load Base Oil A Base Oil A plus Schifi BaseA/SbF Base Oil A plus Schitf Base A/TiFi. Base Oil A plus Schifl BaseB/SnF Base Oil B Base Oil B plus Schifi Base B/SllClz (2:1)

Example VI The load carrying and anti-scuff properties of lubricantcompositions containing different percentages of the adduct of PrimeneJMT/2-ethylhexaldehyde Schifl? base with titanium tetrafluoride wasdetermined in the Ryder gear test. In the Ryder gear test (Federal TestMethod 6508) the lubricant is employed to lubricate two spur gears in aPratt and Whitney gear and lubricating tester. This tester was operatedwith a gear speed of 10,000 rpm. and with an oil inlet temperature of165 F. A loading pressure of 5.0 p.s.i. was applied during break-in.After minutes the tester was shut down and the gear examined for thepercentage of tooth area scutf on each tooth. The procedure was thenrepeated using a high load pressure with increments of 5 p.s.i. until22.5 percent of the total tooth area on the driving gear had beenscufi'ed, the load applied in this run being considered the scuif load.The tooth load in pounds per inch of tooth width was then calculated.The base oil employed was the same as base oil A employed in Example Vabove. The results of this test are given in Table III. TABLE III.LOADCARRYING AND A-NTI-SCUFF PROP- ERTIES BY THE RYDER GEAR TEST Oilcomposition (wt): Ryder gear test, p.p.i. Base oil 2300 Base oil+1%Schiff base/TiF 4320+ Base oil+.5% Schifi" base/TiF 4350+ Base oil+0.1%Schilf base/TiF 3980 The lubricating compositions containing theabovedescribed Schifi base-inorganic halide adducts have markedlyimproved load carrying and anti-scuff properties. They also exhibit goodcorrosion resistance, oxidation resistance and storage stability. Thesevaluable properties make the lubricants of the invention suitable for abroad range of lubrication applications.

It is understood that the lubricating compositions of the invention cancontain numerous additives conventionally used to improve the propertiesof lubricating oils. Commonly employed additives are the methacrylatesas V.I. improvers and pour point depressors, the alkylphenols asoxidation inhibitors, alkaline earth metal salts of petroleum sulfonatesor alkaryl sulfonates as detergents, metal dialkyl dithiophosphatecorrosion inhibitors and silicone anti-foam fluids.

Obviously, many modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof and, therefore, only such limitations should be imposed asare indicated in the appended claims.

We claim:

1. A lubricating composition comprising a major proportion of alubricating oil and 0.05 to 10 percent by weight of an oil-solubleadduct of a Schiif base and a halide having the formula:

in which R is an alkyl radical having from 1 to 30 carbon atoms, R isselected from the group consisting of hydrogen and an alkyl radicalhaving from 1 to 18 carbon atoms, the sum of the carbon atoms in R and Rbeing at least 12, y is an integer from 1 to 6, M is a polyvalent cationselected from the class consisting of boron, aluminum, titanium, tin,zinc, copper, cadmium, magnesium, mercury, zirconium, antimony, bismuth,manganese and iron, X is a halide ion selected from the group consistingof chloride, bromide and iodide ions and in the case of diva lent tinand the cations having a valence of 3 to 4 the fluoride ion, and z is aninteger from 2 to 4 equal to the valence of M.

2. A lubricating composition according to claim 1 in which M istitanium.

3. A lubricating composition according to claim 1 in which M is tin.

4. A lubricating composition according to which M is zinc.

5. A lubricating composition according to Which M is copper.

6. A lubricating composition according to which M is antimony.

7. A lubricating composition according to which MX is titaniumtetrafluoride.

8. A lubricating composition according to which MX is stannous fluoride.

9. A lubricating composition according to claim 1 in which MX isantimony trifiuoride.

10. A lubricating composition according to claim 1 in which MX isaluminum trifiuoride.

11. A lubricating composition according to claim 1 in which said halidehas a water solubility greater than 0.2 mole per liter at a temperaturein the range of 15-100 C claim 1 in claim 1 in claim 1 in claim 1 inclaim 1 in References Cited by the Examiner UNITED STATES PATENTS2,226,427 12/1940 George et al 252-497 2,978,413 4/1961 Odell et al.25249.6 3,201,350 8/1965 McHugh 252-515 3,216,969 11/1965 Cyba 260566 XDANIEL E. WYMAN, Primary Examiner. W. H. CANNON, Assistant Examiner.

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF ALUBRICATING OIL AND 0.05 TO 10 PERCENT BY WEIGHT OF AN OIL-SOLUBLEADDUCT OF A SCHIFF BASE AND A HALIDE HAVING THE FORMULA: